Stacking apparatus

ABSTRACT

A stacking apparatus is disclosed having conveyor belts and chutes governed by flaps and containing blower nozzles for depositing blanks into the chutes. Stacking platform establishing horizontally extending rods move down in the chutes while similar rods move up but in a retracted position, to serve as platform for the next stack. The rods run in horizontally stacked guide plates serving also as partition between two adjacent chutes. Each guide plate supports two rods respectively for the two adjacent chutes. Adjacent plates in a stack are moved in opposite direction. A common drive for all plates is geared to the principal drive for the conveyor belts.

United States Patent Lorenz Hupl'aul Fuerth, Germany [72] Inventor [S4] STACltlNG APPARATUS 12 Claims, 3 Drawing Figs.

[52] US. Cl 271/641, 271/88 [51] lint. Cl B65h 31/IM [50] Field of Search 271/64, 86, 88, 75

[56] l telerences Cited UNITED STATES PATENTS 2,521,075 9/1950 Matthews 271/88 2,533,422 12/1950 Braun 271/64 Primary ExaminerJoseph Wegbreit Attorney-Smyth, Roston & Pavitt ABSTRACT: A stacking apparatus is: disclosed having conveyor belts and chutes governed by flaps and containing blower nozzles for depositing blanks into the chutes. Stacking platform establishing horizontally extending rods move down in the chutes while similar rods move up but in a retracted position, to serve as platform for the next stack. The rods run in horizontally stacked guide plates serving also as partition between two adjacent chutes. Each guide plate supports two rods respectively for the two adjacent chutes. Adjacent plates in a stack are moved in opposite direction. A common drive for all plates is geared to the principal drive for the conveyor belts.

STAClltllhl G APPARATUS The present invention relates to a device for the formation of stacks, a stack to comprise a selectively variable plurality of flat elements such as flexible blanks or the like. These blanks are to be transported individually by means of suitable arranged conveyor belts defining a narrow transport channel, in that the conveyor belts are arranged to face each other across a narrow gap, and they run at similar speeds to transport the blank in between them. The blanks are to be stacked in at least one chute provided with receiver elements supporting the blanks of a stack during formation thereof but permitting withdrawal of a completed stack. in addition, the stacking device will include blowers to control stacking in a chute by blowing, for example towards the edges of a blank when about to drop into the chute.

Devices of the type generally referred to above are usually placed ahead of packing equipment and the task exists to collect a large number of rapidly appearing items such as sheets of paper, cloth or any blanks and to organize them into stacks subsequently to be backed. The disposal speed for such blanks, folded or unfolded, such as napkins, handkerchiefs or the like is limited by the particulars of the known stacking equipment. The known methods for mechanically depositing such blanks are limited in speed of depositing and stacking, so that this sorting and stacking process is regarded as the weak link in the chain" processing such blanks, particularly in view of the fact that presently the production speed, i.e., the rate of producing such blanks, is considerably higher than the speed for depositing and stacking them, so that known depositing and stacking equipment hampers an overall increase in production speed. In addition, it has to be considered that any increase in depositing and stacking speeds increases the difficulties concerning careful and gentle handling of the blanks, and also operational safety becomes increasingly difficult.

A particular improvement over otherwise known stacking devices is, for example, disclosed in German Pat. No. 1,205,987 disclosing endless conveying means engaging the blanks from above as well as from below on opposite sides and cooperating with a blower nozzle system arranged above the stacking chute and directing a stream of air towards the edges of the blank. in addition, the bottom of the chute can be opened for removal of a completed stack. Stacking actually results by blowing the blanks towards the closed bottom of the chute. Blower system and bottom opener are controlled by a common control device.

This arrangement has generally operated satisfactorily, but guidingof the blanks between upper and lower conveyor belts hampers the pneumatically controlled removal of the blanks for depositing into the chutes. In addition, a certain delay is required for opening and closing the two basketlike parts of the collecting device, These features are regarded as detrimental. Furthermore, it appears that particularly the respective first blanks for each stack have to proceed over relatively large travel path, until finally reaching the bottom of the collecting member by operation of blowing air. In view of the required clean guidance at the shortest possible time, this is not an ideal solution.

The problem to be solved by the present invention is to increase the depositing and stacking speed by choosing principles of construction deviating from construction principles underlying the known depositing and stacking devices. in accordance with one aspect of the present invention, and in the preferred embodiment thereof, it is suggested to provide flaps along the travel path of longitudinal conveyance of the blanks. These flaps, when closed, cover part of the top of the chute and form part of the lower runway of the conveyor path, in between individual conveyor belts. A flap operates, when open, as switch to divert a blank into the respective stacking chute. Blowing nozzles are to be provided in these flaps as well as in certain bridges likewise covering the remaining portion of the top of the chute. Each chute is provided with a plurality of receiving elements progressively moving down as the number of blanks in the stack increases during stacking. These receiving elements as moving down project into the respective chute to establish a stacking platform. Similar additional receiving elements move parallel thereto but in up direction and having retracted position relative to the interior of the chute. This way the receiving elements for another stack to be formed next are moved in position and they are caused to protract, when the receiving elements having supported ajust completed stack retract to permit withdrawal of this just formed stack, for example, through lateral conveyors. At the same time, the several receiving elements reverse their respective up and down motion, to obtain overall uninterrupted or practically uninterrupted stacking operation.

As stated, along the guide path for the blanks and aligned with the upper entrances of the chutes, as well as above thereof, there are provided respectively lower and upper conveyor belts. The upper belts follow each other in more or less continuous and practically gapless sequence. The lower conveyor belts, form the principle runway; they are, however, interrupted by the respective chutes. The resulting gaps in runway are covered in parts by the flaps; the remainder of each chute is respectively covered by bridges. Thus, lower belts, flaps (when closed) and bridges, form a more or less continuous runway. This arrangement avoids clamping of a blank between adjacent conveyor belts.

A blank is guided into a chute in that the trailing end of a conveyor belt pushes the respective blank into position below the open flap and also below the bridge. Flap and bridge include blower nozzles directing air in down direction, towards the edges of a blank for depositing it gently but at a deliberate speed upon the top of the formed stack. The receiver members, when having position to project into a chute, move from an uppermost position in down direction at a rate which corresponds to the progressing number of blanks to be deposited in the formed stacks. Each blank, therefore, propagates actually precisely the same path as far as an individual stack is concerned. Furthermore, the immediate protraction of previ ously retracted receiver elements upon. reversal of the receiver elements, as far as up and down motion is concerned, permits uninterrupted depositing. After a stack has been formed, the receiver members, now in up position, are caused to protract into the chute to form a new stacking platform for the next stack to be assembled, while the previously formed stack is moved lateral out of the chute in that the retracting receiver elements, having supported that stack up to that point, seat the stack onto lateral conveyor belt.

In accordance with another feature of the invention, the final up and down moving step of each group of receiving members is larger than any of the preceding steps during the formation of a stack. Thus, the receiving elements that moved down with and supported that stack, are moved down by a greater step than before so that the top of a stack as a whole is moved below the level of the previously retracted receiving members which are now near the top of the chute. This way it is avoided that these previously retracted receiving members, which now will be protracted after having obtained uppermost position, damage the top portion of the just completed stack. Additionally, of course, the large down moving step of the now completed stack places that stack closer to the conveyor device for moving the stack, for example, to a packing machine.

in accordance with another feature of the invention each chute has associated four receiver elements whereby, for example, each such element is in fact comprised by a plurality of rods extending in the same horizontal plane. Two such receiver elements, i.e., two such pluralities of rods, are always at the same level in relation to each other and are guided in opposite sides of the chute. Thus, two groups of rods form one stacking platform at any instant when extended into the chute and two additional groups of rods are retracted. The extended rods move down as stacking platform, the retracted ones move up. Each group of rods covers only about half of the cross section of a chute. Rods in the same vertical level face each other across the chute, and the rods when protracted, have only a small distance from each other, so that they provide in fact a stacking platform or bottom that is closed to the extent required for supporting a stack of blanks.

As stated, each receiving element is comprised ofa plurality of longitudinally movable rods, and all rods of the two receiver elements cooperating in the same plane, are located in a common plane, This construction is economical to make and, in addition, it is of advantage to provide individual drive mechanisms for protracting or retracting each rod. Individual support and guidance for the rods is instrumental in obtaining favorable control conditions for the masses to be moved when a receiving element, i.e., an individual rod changes from protracted to retracted position. Each rod is guided in a suitable bore arranged in a vertically movable guiding plate whereby horizontally aligned rods extending into neighboring chutes in opposite directions can be guided in the same plate. This arrangement saves space and constitutes an inexpensive construction. lt should be noted, that it is permissible to control protraction and retraction of the rods pertaining to different chutes in unison if all stacks are formed concurrently.

In accordance with another feature of the invention each rod provided for selective establishing a stacking platform (together with other rods) is constructed as a piston rod cooperating with a piston which runs in a cylinder bore in the respective guiding plate, and such a piston-cylinder system is pneumatically operated. This way each rod has its own drive but, of course, pneumatic control should concur for all rods, except that half of the number of rods is retracted and the other half is protracted. The provision of individual drives for each rod is of advantage because the masses to be moved are quite small and little inertia is involved in moving an individual rod. Furthermore, there is no need to provide additional linkage between the several rods, which is instrumental in keeping the total mass to be moved as small as possible.

The guiding plates for the several rods as they pertain to the different receiving elements are arranged in groups and sub groups and engage i a comb or interleaved fashion. The guiding plates are horizontally stacked, side by side as to their predominately vertical extension which results in a particularly compact construction. A guiding plate is flanked by one or two guiding plates moving in opposite directions. Therefore, a guiding plate serves as a guide and spacer with regard to neighboring guiding plates moving in opposite directions. Each chute is flanked and established by two such groups of guiding plates. Each group is divided in two subgroups both of them pertaining actually to two chutes, The plates of the two subgroups of a group are interleaved whereby one subgroup moves in one direction, the other subgroup moves in the opposite direction. There are, thus, four subgroups of plates flanking each chute and the plates of respective two subgroups of different groups move in the same direction.

For driving the several guide plates each of them may be provided with one or several, vertically extending but horizontally facing apertures. All these apertures of the several guiding plates, forming one group and arranged between two chutes, are horizontally aligned (except for vertical displacement). They are traversed by an elongated pinion such as a pinion rod or shaft. The pinion rod cooperates with a rack on each plate. The rack may be formed on one long side of the aperture in each guiding plate. In accordance with another feature of the invention the racks in the apertures of the one subgroup of guiding plates moving in unison are arranged on one side of the pinion shaft meshing therewith while the racks in the other subgroup of guiding plates, to be moved likewise in unison but in the opposite direction as the first subgroup, are arranged on the other side of the elongated pinion.

As the pinion shaft engages all these racks and rotates in one particular direction, one subgroup of guiding plates is moved up and the other one is moved down. Of course, guiding plates that are moved up have the respective rods therein retracted; guiding plates that are being moved down concurrently have their respective rods protracted to serve as bottom or stacking platform for the stack to be formed in the particular chute. The direction of rotation of the elongated pinion is reversed after the guiding plates have reached upper and lower terminal position, and during reversal, protractive and retractive positions of the rods are changed.

In accordance with another feature of the invention the elongated pinion is driven by a segment gear which can undergo reciprocating rotating motion in dependence upon the feeder speed for the blanks. This particular arrangement is suitable particularly for arrangements with a plurality of chutes, as there may be provided a common reciprocating control rod driving the several gear segments each of which drives an elongated pinion which, in turn, drives the guiding plates arranged in between the succeeding chutes.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention, and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 illustrates somewhat schematically a side elevation and partially a section view of a stacking device constructed in accordance with the principles of the preferred embodiment of the present invention;

FIG. 2 illustrates a perspective and enlarged view ofa block of guiding plates arranged in between two chutes of the stacking device shown in FIG. 1; and

FIG. 3 illustrates, also in an enlarged view, a detail of the driving arrangement for stepwise driving and reversing motion of the guideplates as shown in FIG. 2 which define position of movable stack support bottom.

Proceeding now to the detailed description of the drawings in FIG. 1 thereof, there is illustrated a feeder roll 1 cooperating and in engagement with an endless conveyor belt 2 for driving same. Conveyor belt 2, in turn, cooperates with a second endless conveyor belt 3 in that these two conveyor belts are guided by suitable rolls to run along parallel paths whereby portions of the belts, when progressing in the path, face each other across a narrow gap and over the particular length of the path. That path defines the input section for the stacking device. The blanks to be stacked are conveyed individually by and between parallel progressing portions of the conveyor belts along that bath. Of course, the two belts 2 and 3 are driven to run at similar speeds.

The stacking device includes, in the particular illustrated embodiment, three chutes, 4, 4' and 4" for receiving the blanks and stacking same. The chutes are vertically arranged and disposed in relation to each other in spaced-apart relationship in the direction of transportation of the blanks, prior to stacking thereof. In between these chutes there are provided additional, lower conveyor belts 5 and 5. These belts, as well as belt 3, establish a runway, as each belt is guided into horizontal plane, and progressing portions of these belts run in the same direction in the plane. Directly above these belts, such as 6, 6 and 6", running parallel and codirectional with belt 2 as to their respective progressing, downwardly directed surfaces. All of these conveyor belts 2, 3, 4, 5, etc., are driven by suitable driving and motor means which are not illustrated but which operate for providing similar speed to all of these belts.

The top of each chute 4, 4', 4" etc. is covered by a flap, such as flaps 7, 7', 7" etc. In the closed position the upper surfaces of flaps 7, 7, 7" are essentially coplanar with and form part of the runway established by conveyor belts 3, 5, 5' etc. When open, the flaps serve as switch for redirecting blanks into the respective chutes. Looking in the direction of motion, particularly in the direction of transport of the several blanks, the lower runway includes additionally bridges such as 8, 8, 8" etc., also positioned above the respective chutes and behind the respective flap of the same chute.

Each flap 7, 7, 7" and each bridge 8, 8', 8" is provided with downwardly directed blower nozzles. The nozzles in a flap, when closed, and the nozzles in the bridge next thereto, and covering the respectively associated chute, blow air towards the four edges of a blank, which has just been ad mitted to a chute when the flap was temporarily open. That blank, therefore, is gently urged in down direction.

Receiver elements, such as 9, 9, 9" arerespectively provided for each of the chutes 4, 4', 4'. Generally, they are provided to receive the blanks that have been assigned to the respective chute and to establish a stacking platform which is gradually lowered into the chute. Details of these receiver elements will be described more fully below. Suffice it to say that each chute has two pairs of receiver elements. The two receiver elements of a pair face each other across the chute in the same level. However the elements of one pair only are in a protracted position, i.e., only two elements extend into the chute to form a bottom or stacking platform, while the ele' ments of the other pair are retracted and do not extend into the chute.

The pairs of receiver elements shown in the drawings in an upper position for all chutes, are moved progressively down as stacking proceeds and the number of blanks stacked in the respective chute increases. The up and down movements will also be described in detail below. Down movement of receiver elements serving as stacking platform causes the formed stack to be brought in the vicinity of another conveyor belt for each chute, such as 10, 10' and it)", provided for moving the formed stack laterally out of the respective chute. After the protracted elements in the respective chute and forming the stacking platform have reached lower level A, they are retracted to that the stack becomes seated on the respective belt l0, l0 etc. Thereafter, belts l0, l0 etc. transport the stacks laterally out of the chutes, in directions transverse to the plane of the drawing.

The down motion of the first-mentioned receiver elements (one pair per chute) concurs with up movements of additional receiver elements pertaining to the respective other pair. These latter receiver elements are retracted, and they move up outside of the respective chutes 4, a and 4i". As the retracted receiver elements have reached respective upper end on terminal positions of motion, they are protracted, to extend into the chute so as to form a new stacking platform. in order to permit this change between position of projection into the interior of a chute, and retracted positions, the walls defining the chutes are provided with appropriate and corresponding apertures receiving the receiver elements. After a change in retraction and protraction, the direction of up and down motion is reversed also.

There is provided a continuously operating arrangement in that always one pair of receiver elements establishes a downward moving stacking platform for the particular chute, while the retracted elements of the other pair move up. The latter elements establish a new platform, close to the top of the chute and whenever the previously operating platform has reached lowermost position and has its element retract to seat the stack on the respective withdrawal belt, ill) or ill etc.

The vertical and horizontal guidance of the receiver elements 9, 9' and 9" is carried out by means of guiding plates llll and ill arranged in blocks or horizontal stacks and disposed in between respective two adjacent chutes. The same block of guiding plates is responsible, for guiding those receiver ele' ments which pertain to the two adjacent chutes but project therein from opposite directions. A block ofguiding plates can also be described as a common wall between two adjacent chutes. Such a block or staclt of plates actually serves as partitioning element or divider wall between adjacent chutes. This arrangement permits, therefore, common guiding of half of the stacking platform establishing receiver elements of adjoining chutes, such as, for example, those elements it projecting leftward into chute 4' from the right and those elements i projecting rightward into chute i from the left.

in front of the first and behind the respective last chute one has to use a somewhat modified block of guiding plates, the modification having to do with the fact that they guide only last chute is not illustrated in detail because additional chutes may be provided behind chute 4i", but there is a particular block l2 for the left side receiver elements '9 of the first chute ll.

Construction and function of such a block of guiding plates can be derived as to particulars from FIG. 2, illustrating representatively block llll which is disposed between chute 4i and d and guiding leftwardly extending right-hand receiver elements 9 of chute 4 as well as the rightwardly extending lefthand receiver elements 9' of chute 4'. In order to facilitate orientation, the FIG. 2 shows that particular block of guiding elements and plates on an enlarged scale and in respective view. The upper position receiving element 9 illustrated is composed of a plurality of rods 13a arranged next to each other in a horizontal plane. These rods 33a cooperate, of course, with a similar plurality of rods extending across chute d from the other side, to establish a stacking platform. There is a corresponding group of rods for this chute, which, however, are retracted as well as in lower position.

As to elements 9, there is a corresponding group of protracted and extended rods 13a and a lower retracted group of rods R317. The rods l3 and the rods ll3'a can be re garded as individually arranged in pairs and along a common line and such a pair of rods is disposed in a common guiding plate 14. The plurality of plates M constitutes the guiding means for those rods which are to serve in common for establishing platforms (one half of a platform each for chutes d and 4i).

FIG. 2 illustrates the particular position or phase of motion of receiverelements wherein all those rods in guiding plates 14 are in the upper position. Rods l3 and ll3'a are, or have just been, extended. There are provided additional guiding plates ll l sandwiched in between adjacent ones of the guiding plates 14. Guiding plates 14' are shown in their respective lower positions. The rods llElb' (and similar rods for chute l, on the other side) disposed in guiding plates M are in the retracted position.

Each guiding plate l4 and each guiding plate 114' is provided respectively with two vertically extending apertures denoted R5, for guiding plates 14 and H5 for guiding plates M. The apertures are horizontally aligned to define two horizontally extending apertures traversing the bloclt of plates. One long edge of each of these apertures is provided with a rack such as M and T6. The arrangement is selected to that a rack 16 is disposed on or defined in the left-hand side of an aperture T5 of the respectiveplate M, and a rack 16 is disposed on the long right-hand side of an aperture ll5** of the respective plate M.

Elongated pinions or pinion shafts l7 and 18 project through one or the other of all of these apertures as illustrated. The pinion shafts operate in unison and respectively mesh with raclts 16 on their left-hand side and with racks 16' on the right-hand side. Upon rotation of elongated pinions ll'7 and H8 in similar directions, for example, counterclockwise they drive plates lid down while concurrently guideplates M are being driven up. For reversing up and down motions, the pinions are driven to rotate in the opposite direction. The curved arrow denotes engagement with a common drive for the two pinions, particularly for obtaining counterclockwise rotation for each of them. it will be understood that the vertical plate movement could be produced with a single pinion, however, it was found that the double pinion arrangement improves considerably stability and lateral guidance of plates l4; and 114'.

After guiding plates ll lhave moved down while the guiding plates lll have moved up, the relative positions of the rods such as M, llEl'a and lil'b and others are reversed, in that the previously protracted ones are retracted, and the previously retracted ones are protracted. Rods disposed in a common guiding plate are operated in unison, amounting to displacement in opposite directions.

in order to obtain this result, each rod, such as i3, 713%: and l3l'b, is actually constructed as piston plunger or piston rod there being a piston such as in the interior of each plate and for each of these rods 13, etc. The respective position runs in a cylindrical bore 19 arranged in the upper part of the respective guiding plate and serving as piston chambers. The two piston chambers in each guiding plate are fluid conductively connected, and they connect to a common duct such as 22 traversing lengthwise the guiding plate and terminating in a stud or inlet nipple 22 to which is connected a hose for selectively supplying air pressure thereto or for venting duct 22 and the piston chambers from that inner side.

As pressurized air is applied to ducts 22'22, the two pistons are, so as to speak spread apart so as to cause protraction of the respective two rods 13 and 13a. The other, oppositely directed ends of the pistons chambers, such as 19, connect to ducts 21 respectively terminating in two studs 21' to which are connected hoses leading also to a pressure control system. Ducts 21 are vented when air pressure is applied to duct 22 during protraction of the rods.

In order to cause retraction of the rods 13 and 13'a, ducts 2121 are pressurized, causing the two pistons to move towards each other. Concurrently, ducts 22'22 are vented. The airflow for pressurization is indicated by delineated arrows. Of course, there is such a duct system for each of the plates, and they are operated in phase opposition as to plates 14 and plates 14'. The respective hoses may connect to suitable manifolds and suitable valves control pressurization and venting. These valves, in turn, are actuated by limit switches which respond to terminal positions of the guide plates.

Elongated pinions 17 and 18 are driven by and through a rotatably positioned gear segment 24 which, in turn, is mounted for rotation on a shaft 23. This driving arrangement is shown generally in FIG. 1 there being a gear segment for each of the blocks 11 and 12. Each gear segment is constructed as double arm rocking lever, with a pivot point established by a shaft 23. The gear segment portion constitutes one arm, extending on the circle outlined upon pivoting about the pivot point and the axis of shaft 23. The other arm carries roll 25 supported in roller bearing or cam fashion in a guiding portion 27 which, in turn, is secured to a rod 26. Rod 26 moves back and forth along its horizontal axis, thereby causing the segments to rotate about the respective shafts 23, clockwise or counterclockwise depending upon the direction of motion of the rod. Rod 26 is moved in dependence upon the speed with which the blanks enter the system, and that speed in turn is represented by the rotation of speed of roll 1 and by the spacing of the blanks. After the respectively required number of blanks has been stacked, rod 26 has a particular position corresponding to lowermost position of all protracted receiver elements defining stacking platforms in the chutes. Now the direction of motion of rod 26 is reversed, through suitable control exerted upon the rod by a heart-shaped, continuously rotating cam 28. Cam 26 rotates at a particular speed and thereby shifts rod 26 back and forth resulting in alternating up and down movement of each guide plate 14 con curring with alternating down and up movement of each guide plate 14'.

Details of cam 28 are illustrated more fully in FIG. 3. The cam runs between and cooperates with two guide rolls, 29 and 29' individuallyjournaled in rod 26. The heart-shaped cam 28 is secured to a shaft 30 which carries also a detent gear 31. This detent gear 31 is moved in steps by operation of a lever 32. Lever 32 is rotatably mounted on shaft 30, undergoing rocking motion thereon, and it engages the respective detent teeth of gear 31 by means ofa pawl 32a on lever 32. The pawl is spring loaded to engage the respective detent under spring pressure.

Lever 32 is actuated (rocked) by means of an actuation rod 34 which is eccentrically linked to a wheel 33 (FIG. 1). Wheel 33 is driven by means of a chain or a suitable, toothed belt or the like, in synchronism with driving of the entire arrangement and at a rotational speed that is proportional to the quotient of: frequency of delivery of the blanks over the number of chutes.

At the particular speed of wheel 33, rod 34 reciprocates and rocks lever 32 accordingly for actuation of the pawl-detent arrangement. In the particular embodiment illustrated the arrangement is constructed that the detent wheel 31 is moved angularly by two detent teeth for each actuation of lever 32 and the control rod 26 is moved correspondingly by a particular step and in a direction determined by cam 28. Cam 28 moves rod 26 back and forth for one revolution corresponding to the formation of two slacks in each chute. The number of detent teeth on wheel 31 over about each half circle deter mines the number of steps. The rotational speed of wheel 31 determines the speed of down movement of each platform in the chutes and in relation to the frequency of delivery of blanks, the number of blanks per stack is determined therewith. For example for forming stacks each comprised of 10 blanks the following has to be considered. it is desirable to correlate the stepwise down motion of the receiver platforms in each chute with the delivery of blanks to the stacksv Thus, the number of steps should correspond to the number of blanks per stack. Formation of one stack requires one-half rotation of heart-shaped cam 28 and motion of rod 26 in one direction between two points of reversal, Therefore, there are provided two rows of detent teeth on the circumference of wheel 31, and toothless gaps separate the two rows. Each of these rows is comprised of 19 detent teeth. The two rows of teeth may, for example, be separated by similar gaps the length of which are multiples of the respective tooth-to-tooth distance. The two gaps between the two rose of teeth on the circumference of wheel 31 are diametrically opposed on the wheel 31. This permits ten steps for obtaining one-half revolution of cam 28, for moving a stacking platform in a chute completely down from upper most position.

As a stack receives a respective last blank a relatively larger downward displacement step of the respective platform establishing receiver elements, such as the rods 13, etc., is required. For obtaining this larger step there is another detent wheel 36, provided likewise on shaft 30, being secured thereto but having only two teeth which are diametrically opposed on the circumference of the wheel 36. These two teeth have an angular phase position in relation to the detent wheel 31, to be aligned respectively with the respective 19 tooth of each of the two rows of teeth on detent wheel 31. Alignment, of course, referring to alignment in a direction parallel to the axis of common drive shaft 30.

Detent wheel 36 is moved by means of a lever 37 likewise having a spring biased pawl 37a for respective engagement of a detent tooth to obtain turning of detent wheel 36 and of shaft 30. The lever 37 can likewise undergo reciprocating motion by operation of a rod 39 articulated to lever 37 and being on the other hand linked eccentrical to a wheel 38. Wheel 38 has the same rotational speed in numbers of revolution as has the drive wheel 33 or the other detent operating mechanism but the degree of eccentricity of linking rod 39 to wheel 38 is larger than the eccentricity of linking rod 34 to wheel 33.

The aforedescribed arrangement for moving rod 26 back and forth operates as follows: During the respective first nine steps of detent wheel 31, pawl 37a on lever 37 merely runs over that smooth circumference of detent wheel 36, there being no detent tooth to engage. With the tenth step the pawl 37a on lever 37 causes shaft 30 to rotate over an angle which is equal to the angular width of the gaps between two rows of teeth on detent wheel 31. Consequently, shaft 30 turns over an angle that is larger than each angular regular step by operation of detent 31. During this larger angular progression step of shaft 30, pawl 32a of lever 32 merely slides over that particular gap of detent wheel 31. Concurrently, cam 28 runs through an angular position range corresponding to and resulting in direction reversal of rod 26, causing the guide plates 14 and 14 to reverse. At the end of the larger angular step pawl 32a on lever 32 is positioned in front of the first detent tooth of the next row on wheel 31, and with the next rocking step exerted by rod 34; upon lever 32 regular angular progression as described proceeds.

In order to better understand operation of the device in accordance with the present invention it should be mentioned that, in case of concurring formation of stacks in the several chutes, the distance between two succeeding chutes 4i and i or 4' and i" must be about equal to the distance between two sequentially arriving blanks as sequentially entering the system on the runway established by belt 3, etc. The stacking device operates through a plurality of different operating cycles, which are dependent upon an input operating cycle that is not part of the machine but is associated and interdependent therewith. individual blanks are to be provided to the machine at a particular rate, and that rate is determined by two factors. First, there is the speed of the conveyor belts, particularly of the feeder belts 2 and 3. Additionally, the feeder rate for blanks is given by the spacing requirement for the blanks, to be equal to distance between adjacent chutes. The feeder rate is thus equal to belt speed over center to center distance of the chutes along the linear path oftransportation.

A first operating cycle of the machine itself involves periodic opening and closing of the flaps '1", '7', etc. At first all flaps ti, 7' and 7 are closed and remain closed until the phase of the transported plurality of blanks is such that there is a blank just about in front of each flap. in that instant a control pulse is derived, for example, from the principal feeder roll 1 serving to control opening of the flaps, to assume the dashed position, so that the respective blanks enter the respectively associated chutes. The flaps open briefly only, i.e., for a period of time sufficient to admit completely a blank to a chute. The flaps open at a rate that is equal to the above defined feeder rate for blanks divided by the number of chutes.

Concurrently with flap opening, the air nozzles therein and in bridges 8, ti and 8" operate in order to provide a certain breaking of the blanks, which breaking effect precedes the disposing proper of a blank in the respective chute and is significant for obtaining satisfactory placement. Shortly after the flaps reclose, the next group of blanks pass over the polished surfaces of the closed flaps and bridges until again there is a blank in front of each flap and the aforedescribed opening and disposing operation is repeated.

it will be understood that opening and closing offlaps 7' and 7", as well as valves controlling of flow of pressurized air to the blower nozzles, can be controlled by various means such as a solenoids, electromagnets, pneumatic and hydraulic equipment etc. It will have to be mentioned, however, that a conventional cam drive using teeth belts driven from the principal input roll 1 were found particularly suitable and quite economical.

Concurrently with the periodic flap opening, the platform establishing extended rods of receivers 9, 9' etc, are moved down in steps, in that the longitudinal movement of rod 26 is translated by segment gears 24 in a rotary motion of pinions i7 and llti which, in turn, drive the guide plates M and Ml. When the pawl on actuator 37 turns shaft 36' by a relatively large, angular step, the down moving guide plates and, therefor, the protracted platform establishing rods 13 etc. move down by a large step, and are retracted for seating the formed stacks onto lateral withdrawal belts Flt), llti etc. Concurrently, the previously retracted rods of receiver elements 9, 9' etc. are extended into the space above the completed stacks, dividing so to speak, the completed stacks from the new ones about to be formed. Shortly thereafter cam 2d retracts rod 26 and the next stacks are formed. This cyclic movement of rod 26 involves formation of two stacks per complete reciprocating cycle. That cycle rate is equal to the blank feeder rate, divided by the product of the number chutes and twice the number of blanks per stack.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

lclaim:

1. Apparatus for stacking blanks which includes endless conveyor belts facing each other across a narrow gap for loniii) gitudinally transporting the individual blanks, there being at least one upper belt with a downwardly directed conveyor sur face as progressing in direction of transportation and facing at least one lower belt at an upwardly directed conveyor surface thereof, and progressing in synchronism with the upper belt, comprising:

first means defining a vertical stacking chute;

a flap covering a portion of the upper entrance of the chute and having a closed position for defining a continuation of the travel path of said upwardly directed belt surface, the flap having an open position for admitting a blank to the chute;

blower nozzles on the flap for blowing air towards the edges ofa blank after having being admitted to the chute;

first receiver members having retracted and protracted positions and defining a stacking platform in the chute when in the protracted position;

second receiver members having retracted and protracted positions and defining a stacking platform in the chute when in the protracted position;

second means coupled to the receiver members to provide up-movemcnts of the first members and down-movement of the second members during a first cycle, while the first members have retracted position and the second members have protracted position, and providing reversely directed movement of the members in a succeeding second cycle, first and second cycles follow each other in alternating cycles; and

third means for exchanging protractive and retractive positions of the members upon changeover from the first to the second cycle or vice versa.

2. Apparatus as in claim 1, the second means operating to provide down movement of protracted first or second members in steps, following each other in synchronism with feeding of blanks for stacking, and including means for moving the down moving members at the end of the respective cycle at a larger step than the synchronous steps during stacking proper.

3. Apparatus as in claim it, there being a first and a second pair of receiver elements, each pair operating in the same horizontal plane, moving up and down.

t. Apparatus as in claim 3, each receiver element comprising a plurality of rods disposed for placement and displace ment in a common plane for the rods pertaining to the same pair of elements, there being means for supporting the rods of the plurality for vertical movement.

5. Apparatus as in claim 4, the means for supporting a rod comprising a vertically movable guide plate, there being a first and a second plurality of such guide plates, the first plurality supports the rods of the first pair the second plurality support ing the rods of the second pair, the plates of the first plurality interleaved with the plates of the second plurality.

6. Apparatus as in claim 5, each rod including a piston, the respective guide plate having internal chambers defining a piston chamber, the third means including fluid means operating the piston.

7. Apparatus as in claim 5, the horizontally stacked guide plates traversed individually by aligned apertures;

the second means including pinion means traversing the apertures, the guide plates of the first plurality provided with rack toothing at the respective apertures meshing the pinion for movement in up or down direction upon rotation of the pinion in one or the opposite direction, there being means to drive the pinion.

8. Apparatus as in claim 7, the apertures of the guide plates of the second plurality likewise provided with rack toothing disposed to mesh the pinion for movement opposite to the guide plates of the first plurality.

9. Apparatus as in claim it, the pinion means comprising an elongated pinion.

10. Apparatus as in claim '7, the pinion means additionally meshing a segment gear, there being means for reciprocating the segment gear to move in one direction during first cycles and in the opposite direction during second cycles.

11. Apparatus as in claim 1, the first and second receiver means each including a pair of receiver elements, the elements of each pair facing each other across the chute, at a small distance when protracted, at a larger distance when retracted, protraction and retraction of the elements ofa pair carried out in opposite direction.

12. Apparatus as in claim 1, there being a plurality of chutes along the transport path of the conveyor belts to form plural stacks concurrently, there being first and second receiver members for each chute, the first receiver members for two adjacent chutes including first and second pluralities of rods respectively for the two chutes and disposed in guide plates, 

1. Apparatus for stacking blanks which includes endless conveyor belts facing each other across a narrow gap for longitudinally transporting the individual blanks, there being at least one upper belt with a downwardly directed conveyor surface as progressing in direction of transportation and facing at least one lower belt at an upwardly directed conveyor surface thereof, and progressing in synchronism with the upper belt, comprising: first means defining a vertical stacking chute; a flap covering a portion of the upper entrance of the chute and having a closed position for defining a continuation of the travel path of said upwardly directed belt surface, the flap having an open position for admitting a blank to the chute; blower nozzles on the flap for blowing air towards the edges of a blank after having being admitted to the chute; first receiver members having retracted and protracted positions and defining a stacking platform in the chute when in the protracted position; second receiver members having retracted and protracted positions and defining a stacking platform in the chute when in the protracted position; second means coupled to the receiver members to provide upmovements of the first members and down-movement of the second members during a first cycle, while the first members have retracted position and the second members have protracted position, and providing reversely directed movement of the members in a succeeding second cycle, first and second cycles follow each other in alternating cycles; and third means for exchanging protractive and retractive positions of the members upon changeover from the first to the second cycle or vice versa.
 2. Apparatus as in claim 1, the second means operating to provide down movement of protracted first or second members in steps, following each other in synchronism with feeding of blanks for stacking, and including means for moving the down moving members at the end of the respective cycle at a larger step than the synchronous steps during stacking proper.
 3. Apparatus as in claim 1, there being a first and a second pair of receiver elements, each pair operating in the same horizontal plane, moving up and down.
 4. Apparatus as in claim 3, each receiver element comprising a plurality of rods disposed for placement and displacement in a common plane for the rods pertaining to the same pair of elements, there being means for supporting the rods of the plurality for vertical movement.
 5. Apparatus as in claim 4, the means for supporting a rod comprising a vertically movable guide plate, there being a first and a second plurality of such guide plates, the first plurality supports the rods of the first pair the second plurality supporting the rods of the second pair, the plates of the first plurality interleaved with the plates of the second plurality.
 6. Apparatus as in claim 5, each rod including a piston, the respective guide plate having internal chambers defining a piston chamber, the third means including fluid means operating the piston.
 7. Apparatus as in claim 5, the horizontally stacked guide plates traversed individually by aligned apertures; the second means including pinion means traversing the apertures, the guide plates of the first plurality provided with rack toothing at the respective apertures meshing the pinion for movement in up or down direction upon rotation of the pinion in one or the opposite direction, there being means to drive the pinion.
 8. Apparatus as in claim 7, the apertures of the guide plates of the second plurality likewise provided with rack toothing disposed to mesh the pinion for movement opposite to the guide plates of the first plurality.
 9. Apparatus as in claim 8, the pinion means comprising an elongated pinion.
 10. Apparatus as in claim 7, the pinion means additionally meshing a seGment gear, there being means for reciprocating the segment gear to move in one direction during first cycles and in the opposite direction during second cycles.
 11. Apparatus as in claim 1, the first and second receiver means each including a pair of receiver elements, the elements of each pair facing each other across the chute, at a small distance when protracted, at a larger distance when retracted, protraction and retraction of the elements of a pair carried out in opposite direction.
 12. Apparatus as in claim 1, there being a plurality of chutes along the transport path of the conveyor belts to form plural stacks concurrently, there being first and second receiver members for each chute, the first receiver members for two adjacent chutes including first and second pluralities of rods respectively for the two chutes and disposed in guide plates, there being a vertically movable guide plate for each rod of the first plurality protracting into or retracted from a first one of the two adjacent chutes, the guide plate supporting a rod of the second plurality protracting into or retracted from the other one of the two chutes. The second receiver members for the two chutes including correspondingly arranged rods and guide plates, interleaved with the guide plates for the rods of the first members, the second means including means for moving the first and second guide plates vertically but in opposite direction. 